Nuances between "stoic" and "stolid"
Solution 1:
When describing people, stoic has a particularly heroic connotation. A stoic person really braves everything that man, nature, and God throws at him without complaint. Stolid, on the other hand, is not so: You might use it to describe someone who showcases a simple faithfulness, a "friend through thick and thin," but you might also use the word to describe someone who's plodding and utterly unadaptable to change.
Job, of the Book of Job, is stoic. Watson, of Sherlock Holmes, is stolid.
Solution 2:
There is, of course a significant difference in the etymology of the two words, i.e. stolid cite, which derives from a Latin word meaning foolish or stupid, and stoic cite, which ultimately derives from the Greek for a painted porch (referring to the location where Zeno is said to have taught).
From a usage point of view, I'm of the opinion that stolid means "unfeeling" in the sense of lacking feeling all together (or lacking a particular sensibility), whereas stoic implies bearing up under the weight of one's emotions (the goal of Stoic practice being apatheia, the cultivation of a state of being unaffected by the emotions).
Solution 3:
The part about pleasure in your definition of stoic sounds weird to me, because it is one of the things that differentiate the two words for me: stoic is all about withstanding pain and suffering (will and strentgh), while stolid is more about minor character traits.